title: Joint associations of body mass index and waist-to-height ratio with sleep duration among Saudi adolescents.
abstract: BACKGROUND
  Numerous studies have shown significant associations between short sleep duration and overall or abdominal obesity. However, no study has reported on the joint association of body mass index (BMI) and waist-to-height ratio (WHtR) with sleep duration in adolescents.
  
  
  OBJECTIVE
  To examine the joint associations of BMI and WHtR with sleep duration among Saudi adolescents.
  
  
  METHODS
  A school-based cross-sectional study was conducted involving 2852 secondary-school students (51.7% females) aged 15-19 years, randomly selected using a multistage stratified cluster sampling. Self-reported sleep duration was assessed and BMI was classified into high and low categories according to the IOTF classification, whereas WHtR categories were based on above and below 0.5.
  
  
  RESULTS
  The low BMI-low WHtR category had the longest mean sleep duration (7.27 hours/day), whereas the high BMI-high WHtR group had the shortest sleep duration (7.02 hours/day; p = 0.003) (aOR = 0.832, 95% CI = 0.698-0.992, p = 0.040). In addition, high BMI-low WHtR or low BMI-high WHtR groups didn't significantly associate with reduced sleep duration among adolescents.
  
  
  CONCLUSIONS
  The joint association of high BMI-high WHtR increases adolescent's risk of having reduced sleep duration. Future research should seek to confirm such findings and provide an explanation for this association.
authors.affiliation: Pediatric Exercise Physiology Research Laboratory, College of Education and.
authors.forename: Hazzaa M
authors.initials: HM
authors.lastname: Al-Hazzaa
mesh_terms: D000293:Adolescent; D001823:Body Composition; D001827:Body Height; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity; D009765:Obesity; D012307:Risk Factors; D012529:Saudi Arabia; D057185:Sedentary Behavior; D012890:Sleep / Q000502:physiology*; D013334:Students; D055105:Waist Circumference; D055815:Young Adult